Posted
by
timothyon Sunday March 06, 2011 @02:59PM
from the all-I-want-is-a-big-solar-oven dept.

autospa writes "A University of Arizona engineering team led by Roger Angel has designed a new type of solar concentrator that uses half the area of solar (PV) cells used by other optical devices and delivers a light output/concentration that is over 1000 times more concentrated before it even hits the cells. This comes as a result of a broader goal to make solar energy cost competitive with fossil fuels (target = 1$/W) without the 'need for government subsidization.'"

As a fraction of revenue, these new renewable resources are subsidized far more than coal and oil (coal being the subsidized material you should consider). It is refreshing to see these renewable power sources nearing an unsubsidized parity with coal. That's far more important than complaining about which one is subsidized more.

That's somewhat of a misnomer. The subsidies are mostly tricks to get the oil industry to invest in areas that are not profitable for them and they wouldn't otherwise be at.

In more plain terms, if the subsidies didn't exist, oil companies would not miss them, they simply would not be doing some of the things they are now at the request of the government. Eliminating those subsidies would have no real noticeable effect on price or profit.

They do? Your right, because they can explore other areas of business and develop techniques to deal with it in the future without a large loss. However, that doesn't mean they would continue to do so if they were removed.

I didn't say there wasn't a benefit for them. I said the benefit wouldn't effect their profit or prices if it was removed. Instead, they would just go back to what's normally profitable until such time prices are high enough for them to get into those areas on their own.

It's difficult to argue though, that the tax payer should subsidize exploratory ventures for companies which make some of the largest profits on the planet. In short, they could afford these ventures on their own with no help from the taxpayer. It is to their benefit to keep the taxpayer addicted to oil as long as possible. About the only karmic result of all this is that the oil industry will eventually have to expand into other energy sources or face extinction.

It's difficult to argue though, that the tax payer should subsidize exploratory ventures for companies which make some of the largest profits on the planet. In short, they could afford these ventures on their own with no help from the taxpayer. It is to their benefit to keep the taxpayer addicted to oil as long as possible. About the only karmic result of all this is that the oil industry will eventually have to expand into other energy sources or face extinction.

There are a few ways in which gasoline in subsidized in the US. First oil firms tend to pay a lower tax. It is not amount, but enough to knock down even Exxon profits a tick. Some distort the truth by bringing up laws that have not existed in 20 years. Such subjects are useful to consider as the repeal of such tax was a increase in subsidy, and likely did contribute to the doubling of he public debt as a percentage of GDP during he Reagan administration, from around 30% to well over almos 70%.

Wikipedia had some more data before, I would swear it... It may have been 5 years ago, however when the tax came up again...:) Anyway, another link. http://www.taxfoundation.org/publications/show/1168.html [taxfoundation.org] And yes, I confused 50 cents with 50 percent. But once you factor in all the other taxes, it works out to almost $2 a gallon in 2005, so not really that far off.

As for the sales tax, that varies by state. Buy in all they states I have shopped in recently, food components (beef, cheese, milk) have

This surely depends on exactly what you consider a subsidy. E.g., I count the presence of US troops in the Middle East as an oil subsidy, so I count oil as being heavily subsidized.

If you don't count that, then do you count all the money spent by the government to build and maintain the roads? If not, why not? (I can see an argument that some of that money isn't a subsidy, as it's only paying for things that would be needed even if gasoline engines didn't exist, but not most of it.)

First get to the crux of the matter. Fossil fuels are not being subsidised, lets just through that lie away, corporate profits are being subsidised.

Those elected representative, elected upon the basis of unlimited advertising and PR=B$ funded by corporate dollars are simply and corruptly returning those campaign investments at something like a thousand to one return as corporate profits subsidies.

Corporations are generating returns of something like 10,000% profit on their campaign contributions. Corru

"We in the West are pretty clean for the most part - it's getting India, China and other developing countries to clean up..."

What the hell are you smoking? Or more aptly, what planet are you living on?

A person living in China is responsible for 17% as much greenhouse-gas emissions as is a person living in the United States.A person living in India is responsible for 8% as much greenhouse-gas emissions as a person living in the United States.

What the hell are you smoking? Or more aptly, what planet are you living on?

I think it's more a question of what he's NOT smoking. Only hippies and potheads would look at GHG output as a measurement of how "clean" a country is. Not to mention the foolishness of comparing per-capita emissions between two nations of such wildly different industrial capability. It's like claiming that the homeless guy who keeps shitting in the middle of the street is more "clean" than me because he doesn't have a car.

Sorry, but of course their numbers look good. Take away all their outer areas and the populations who basically are barely powered by anything and you get more reasonable. Look at their air quality in their major cities. Check their rivers and the like.

Per capita and they are broke too, but I don't think its a fair number to evaluate the earning power of those with modern jobs.

You know what? Visit Shanghai, then visit LA, and let me know which you think is cleaner air wise.

The US may have issues too, but that doesn't justify cherry picking data. Using per capita to compare US and China on something like pollution is almost to the level of Fox News statistics reporting. It's like trying to compare Arizona or Nevada to Japan, disingenuous at best.

For some reason people love to glorify China right now because of their economic growth. China is basically a third world country with a privileged class that gets to live in the large cities, it's economy is so large because of the sheer size of the population.

China has passed the US in electricity production but their pollution controls are near non-existent.

So you must think that an American has a (god given?) right to emit GHGs 6 times as much as a Chinese person and 13 times as much as an Indian citizen.

Who should have to "clean up" first, the person emitting 6 times (13 times) as much, or the other person.

Per person is the only fair way to count it. Otherwise you are not so subtly admitting that you value some people (by citizenship) more than you value other people, and that the privileged people (the special people) have an inherent right to contribute mo

Actually, you are comparing 1 billion people to 300 million people and clearly lack an understanding the issues China is dealing with.
China easily has a few hundred million people living in large urban areas with emissions worse than that allowed in the U.S.

Have you forgotten about the Olympics already? China had to shut down almost half of their urban factories to clean the air enough so athletes could compete. There is no where in the U.S. with air quality that poor and somehow you're trying to say they

You do realize don't you that it is American and British oil companies exploiting the resources of Nigeria and leaving them with a massive pollution mess to clean up, right? Sorry but in global evironmental exploitation and degradation, Western multi-national companies and the Western consumers (I'm guilty too) they sell to are by an order of magnitude the worst culprits on the planet, and have been for 60 years at least.

The US BY ITSELF is right now responsible for half of the worlds pollution...yet it accounts for only 1/22th of global population.

This is, of course, complete bullshit. The number is nowhere near what you quote. Moreover, most of those figures include CO2 output as "pollution". If we just stick with actual pollution, the picture looks a lot different [allcountries.org].

A watt is a unit of power, a watt hour is a unit of work. The goal is $1/W which means that a 1000 W system, which produces ~8KWh per day (more further south), only costs $1000, and would pay for itself in about three years, making it economically viable for most people.

Does the angle of the sun come into play here? Is it really the same at 4PM as at noon? Or is 1000 W an average?

A number like 1000W would refer to the peak power output that you'll get from it with the solar cells perpendicular to the sunlight with optimally clear skies. Since the earth receives a maximum of about 1100W/m^2 of solar energy, and ordinary silicon cells are about 12% efficient, you can expect such a system to be a little less than 10 m^2 in size.

No because the sun doesn't shine 24 hours per day. Also solar panels do not product 100% of their rated output if partially covered by shadows, debris, etc. Also you normally don't see solar panels that move to maintain the optimal angle with the sun except in very expensive set ups. Therefore you often need many more Watts' worth of solar panels than what you calculate your electrical usage as.

The short Answer is "NO". The reason for this is you never figure on more then 5 hours of Peak Sun unless you're at the equator, where you can figure 8 hours. The reason for this is pretty simple. It's called Axial Tilt, resulting in our seasons.

Why the 5 hour figure is simple and it's called Winter. That's when you have less sunlight that provides energy due to angles of incidence. Sure a PV panel can provide some output if faced directly at the sunrise but until 9am it's going to continue increasing as th

And in practical terms, you only base calculations for input on 4-5 hours/day - roughly 9:30am to 2:30pm, because power levels from the panels are relatively low outside those hours. Unless of course, you're using a fancy motorised rig to make the panels follow the sun across the sky during the day, and they consume almost as much energy as they produce - every solar installer I've spoken to said the same thing - take the money you want to spend on the motorised rig, and spend it on a couple of extra PV pan

Electric power bills tend to have at least two line items. One is for actual used energy in $/kWh. The other is a monthly service fee, which for larger customers may include provisioned power capacity in $/W/mo.

I see. so 1MW system can deliver 1000 kWh every hour. At $0.11 running 24/7 it could theoretically bring in $964,000/year and basically pay for itself. Assuming everyone had to pay 11 cents (industry probably pays a lot less, these are just so numbers I made up).

1) Solar panels produce direct current, not alternating current. Direct current is almost impossible to transmit across any meaningful length of electric cable.

2) Converting DC to AC is possible, however there are efficiency losses and thermal losses - these come out of your "profit"

3) At some point you are going to need to replace your solar panels - they only last 15-25 years. You need to set money aside for this, unless you plan on shutting down your plant at the end of 15 years.

Direct current is almost impossible to transmit across any meaningful length of electric cable.

Humorously, you have it exactly wrong. The longer the cable, the (relatively) cheaper the cost of HVDC conversion gear vs the rest of the project.

The power delivered by a AC line is based on the RMS voltage. However you have to insulate to peak, which is somewhat more. Insulation is a pretty major design constraint, as arcs to the ground or towers is kind of a waste of power...

As a very rough guess on a medium length line you can push about 1/4 to 1/3 more power for the same cost if you switch to DC.

The power levels I'm talking about are a couple GWs, distances of dozens of miles, costs vaguely around gigadollars. Capital costs of about a buck a watt per 50 miles, lets say. You can see the motivation of placing plants nearby cities, rather than in the middle of nowhere.

You can do long distance AC, and they used to, it just costs a heck of a lot more.

Hmm? I thought the whole reason we use AC (thanks to Edison winning the argument with Tesla) was because there is less loss over long distances when compared to DC. Edison wanted One Big Plant generating power, and Tesla wanted many small, local plants. I guess I will have to re-read this - I apologize, I'm a biologist not a physicist.

That was the a century ago when people hadn't discovered how to step up and step down DC voltages. There're still problems with transmitting high voltage AC across long distances - many long distance runs are actually HVDC now.

Hmm? I thought the whole reason we use AC (thanks to Edison winning the argument with Tesla) was because there is less loss over long distances when compared to DC. Edison wanted One Big Plant generating power, and Tesla wanted many small, local plants. I guess I will have to re-read this - I apologize, I'm a biologist not a physicist.

You mean the argument that Edison *lost* - he was the big proponent of DC, while Tesla and Westinghouse were behind AC.

Go back and check your history. Edison LOST that argument with Tesla. Tesla wanted AC because it was better for running motors and was more efficient for long distance transmission. Edision wanted DC because its arguably safer.

It is high voltage that is more efficient for long distance transmission. The difference between AC and DC for that is that AC is relatively simple to step up in voltage with a relatively simple machine, a transformer.

Edison wanted DC because it was what he had started working with, and he wanted to keep using it.

The ironic thing though is that high voltage DC is actually kind of dangerous to work with, more so than similar AC voltages. This is because of the way inductance and capacitances behave as the frequency increases. As the frequency increases a capacitance starts to look more like a short, while an inductance starts to look more like an open. At DC (IE, at 0 Hz), it is the opposite. In DC, an inductance will

100 years? May I see a source please? Everything I have read states 25 years TOPS. And that is for regular use. When you bombard them with 1000x more light I'm sure you don't improve their useful life, either. You can't cheat entropy that way. Not in this universe, anyway.

Bottom line is if solar can get to $1 for every installed watt, you will be seeing solar installed everywhere

I agree with that, and believe me, I WANT solar to reach that price. It seems like a great energy source (after all, the sun po

What it probably means is they're scammers. Capital costs for coal and nuke run from $1.50 to $3.00 per watt installed. They're claiming $1 per watt. The problem is no matter how unconventional the heat source, no matter how magically free, the employee lunchroom costs $ per plant, the parking lot paving costs $ per plant, the pipes from the magic heat source to the turbines costs $ per watt, the turbine itself costs $ per watt, the water pumps and filters cost $ per watt...

What it probably means is they're scammers. Capital costs for coal and nuke run from $1.50 to $3.00 per watt installed. They're claiming $1 per watt. The problem is no matter how unconventional the heat source, no matter how magically free, the employee lunchroom costs $ per plant, the parking lot paving costs $ per plant, the pipes from the magic heat source to the turbines costs $ per watt, the turbine itself costs $ per watt, the water pumps and filters cost $ per watt...

PERHAPS they mean the capital cost of their magic heat source alone costs about $1 per watt. The problem is some recent historical nukes (not in the backwards USA, but civilized countries like France, etc) have come in at $1.50 per watt total plant cost delivered. So, on one side, their costs probably will decline as they are new vs the very mature nuke industry. On the other hand, can you build an entire thermal electric plant for well under 50 cents per watt? Then again, can a new tech be nearly as reliable as ancient technology nuke plant?

My impression (and damn these mindless 'articles') is that this is an ultimate goal. That figure isn't unreasonable even if it's cheaper than a coal fired plant. Small scale repetitive parts may well bring down capital costs compared to large purpose build structures - the employee break room is not the big ticket item in a nuc plant. Even if they don't get to the $1/watt figure, you have to remember that typical costs for nuc plants especially have enormous subsidies from the government in terms of was

the pipes from the magic heat source to the turbines costs $ per watt, the turbine itself costs $ per watt, the water pumps and filters cost $ per watt...

RTA, there are no pipes, turbine, pumps, nor filter. It's photovoltaic. I don't know whether they can beat a nuke plant in the real world, but the relative simplicity of this system compared to a nuclear power plant is certainly striking.

Question: Why does everyone seem so focused on Solar cells, which as everyone points out wear out, will need cooling at these temps, etc, instead of molten salt solar power [sandia.gov] where the more heat you create the better it runs and the heat stored in the salt itself can be used as a battery? Was there a hidden gotcha I haven't heard about, or is there some sort of kickback or subsidy for cell production?

Because it seems to me that cells are just the wrong direction to go. With Molten Salt it is basically a big

I agree with you completely in that thermal is a better solution in almost all cases at "power plant size" levels.

Problems:

1) Scalability. You can demo and test and experiment with "one" off the shelf cell if you really want. Even if the plan is to later deploy one million cells at the site all wired in parallel. If you try to run a GW class steam turbine on 100 watts, you're not even going to make it physically warm, much less run. Proof of concept is a bit tough. Also its easy to install 50% more P

Capital costs for coal and nuke run from $1.50 to $3.00 per watt installed.

Absolutely meaningless because I am damned sure a coal burning station or a nuclear power plant do not have exactly the same lifetime. When dealing with capital costs you are interested in a return on your investment. The only way to calculate this is by knowing not only how much it costs up front, but how much it will cost per unit of time and how long it's expected to work. If it stops working before you get your money and opportu

my point is their capital estimate is way low, even if their magic electricity and heat generating box were completely free

On this we agree - but this is typical for anything offered by a university. Scientific knowledge != business acumen. There are bound to be oodles of hidden costs in a brand new industry which are well known in an older, established one. That's why you never want to be the first one in the pool...

RIGHT NOW you can purchase thin film solar panels for $1/watt. Now, this doesn't include the inverters, which add more cost, nor labor or mounting hardware...but we are actually a lot closer to the threshold than you think.

The theory is that if $1/watt is the installed cost of solar panels, including labor and inverters, and you don't have to pay for fuel, and the maintenance costs are very small, it would be cost competitive with conventional power sources. The cost s

But I can buy a whole French Nuke plant, delivered, the whole thing, not just a reactor, for $1.50/watt. Or maybe that was the Russian plant. And it runs 24/7 for years at a time... You're just talking about panels. Not mounting systems. Not active trackers, nor wiring, nor a control building.

I bet I could build a PV ish plant using these $1/watt modules for maybe $1.50/watt. But that only outputs "nameplate power" half the time over the course of a year... Hmmm. Just nuke it.

$1/W means you pay $1 to be able to produce 1 W over the lifetime of the solar cell (usually 20 or so years). Not to be confused with your kWh, we're not measuring the same thing.
Just like if you use 2000kWh per month on your electric bill and try to set up a solar system, don't expect to be able to get away with only installing 2000W worth of solar panels...

If you are using concentrators for solar power you really ought to consider a thermal cycle like a brayton turbine or a sterling engine, rather than solar cells. Thermal cycles tend to have higher conversion efficiencies, the equipment is more reliable, and their power output is more easily converted to grid voltage ( AC as opposed to DC ). Solar cells also tend to see reduced lifetimes when used with very concentrated light. The advantage with cells is pretty much that they don't need concentrators to work, since they don't rely on a high temperature. They can also be used in places where space/weight is an issue, such as on sailboats, rooftops or sattelites. Thus if you are already using a bulky concentrator to get the light intensity up, you may as well use a sterling engine.

If you are doing a thermal cycle with concentrators, you need a *big* system. Small thermal engines aren't much more efficient than garden variety solar cells. (And presumably, concentrated solar would use high-tech cells that rival the efficiency of big heat engines anyway.) That means that you have to use a complex "power tower" arrangement with a field of precision synchronized mirrors pointed at one huge collector. You also need a big cold sink for thermal cycles; most power plants use a bunch of water for that, which is hard to come by in the desert.

The solar cell approach would also have the advantage of mechanical simplicity, and the ability to add capacity in small self-contained increments.

If you are using concentrators you either take a huge loss because solar cell output drops off at high temp (and suffer shortened service life) or you end up with a cooling system for the cells. Once you have the cooling system you should just yield to the physics and accept that the best use of concentrated sunlight is in heat, not direct conversion to electricity. Solar cells only convert a few frequencies (three in the article for this story) while dumping the light over to heat uses much more of the s

So? At the end of the day, overall net system efficiency is what matters. Heat engines will always be saddled with the laws of thermodynamics, which force them to waste much of your enhanced spectrum. Solar cells, without the limitations of the Carnot cycle, can convert more of the available energy in the part of the spectrum that they *do* use.

Solar cells also don't need to be cooled to the same low temperatures that the outlet of a heat engine requires to run efficiently. In the desert, that's much easier

The problem is the Carnot eff at a relatively cool nuke plant is still around/over 33%. Good luck finding a production off the shelf solar cell with decades of operating experience that can dream of reaching 33% efficiency.

If you're willing to try "exotic" PV units, I want to try "exotic" carnot units, like maybe a century old binary fluid system like the old fashioned two stage mercury and water system. Maybe something a little less toxic that vaporized mercury. A century or so ago those ran around 50%

In fact, triple-junction cells are far more expensive than garden-variety PV cells. The cost savings come from the fact that sunlight is concentrated onto a much smaller area of cells. And this is hardly the first company that has applied that idea; for example, see Energy Innovations, Inc. [energyinnovations.com]

Roger Angel has designed a new type of solar concentrator that uses half the area of solar (PV) cells used b

Just one panel, and every panel is identical to every other panel. And every subunit on every panel is identical to every subunit on the same panel and every other panel. This repetitiveness means that once you develop an extremely cheap and fast method for making one solar cell, you can make trillions of them the same way and replace most other forms of power generation.

Stirling cycles and thermal plants have more "fiddly bits" that have to be designed, manufactured, quality controlled, and maintained.

It doesn't work at night when you need electricity to power your lights. Which is especially a problem in the long winter nights when you need to heat your home. Can we please finally put this solar-for-everyone nonsense to bed?

And then you'd have the fun and moral satisfaction of purchasing a new set of heavy duty batteries every year or two. Mind you that would be a very large set, to account for the possibility of many short cloudy winter days in a row.

Which sort of makes my point for me. If the power source needs a diesel backup that's going to be used often enough (ie some/most of the winter?), then it's not it's not as viable a source of renewable energy as that same diesel running on synthetic fuel would be. Unfortunately, there is not (yet) a viable large scale production capacity for synthetic fuel. Equally unfortunate is that people and research funding bodies have this solar pathology tattooed on their brains.

Which sort of makes my point for me. If the power source needs a diesel backup that's going to be used often enough (ie some/most of the winter?), then it's not it's not as viable a source of renewable energy as that same diesel running on synthetic fuel would be. Unfortunately, there is not (yet) a viable large scale production capacity for synthetic fuel. Equally unfortunate is that people and research funding bodies have this solar pathology tattooed on their brains.

I'm mostly in agreement. Another point that few people think about concerning alternate energy plans that incorporate the idea of localized, i.e. per-residence or facility generation as in rooftop solar cells, is how does one provide for emergency situations such as storms & earthquakes where many thousands may be without power.

No big utility company vehicles and manpower out to restore power. This will put the poor, old, and lower-income people at higher risk.

Look into the efficiency of a battery sometime. Unless you buy really expensive ones you lose about half of the energy putting it into and getting it back out. More losses if you are putting in AC and needing AC back out. And the really good (from an efficiency pov) lithium-ion batteries don't suffer many charge discharge cycles before hitting the 50% capacity point generally considered as replacement time. We currently have zero methods to store electricity that are cheap enough and effective enough for use on the grid. All electricity is generated as needed, with vast arrays of 'peaking power' generation capacity that largely sits idle. Believe me, if there were a good way to store electricity the industry would be using it already.

Worse, while electricity can be sent large distances, it is best to generate close to the point of use because of the line losses. So even if we were willing (and shot enough enviromentalists) to cover our deserts with solar arrays we would lose most of the power heating the lines getting it to where the customers are. Same for wind, it mostly occurs in areas where there aren't many people... or more accurately windmills near populated areas attracts more environmentalists.

Blah, blah. Neither of us know enough to say but I am smart enough to observe what the people who DO know are doing. They are building peaking power plants and not batteries. They aren't building flywheels either. And yes I too read that long ago that somebody had hit on the idea to run pumps at night to push water back uphill so they could run the hydro plant during the day when demand was high. But I never read just how efficient that process was, jus

The sound you are hearing is not a diesel generator, it is the background "melody" of your songs. You need to stop letting your grandchildren (whose existence I infer from your five-digit UID) upload the music which is on your mp3 player.

Energy consumption is largest during the day, and thus solar can actually help do some load leveling. Yea, you can't get all the energy from solar, but having the plant peak in power output around noon is actually a good thing.

Who ever claims that solar is for everyone despite a minority of kooks? Anyone sensible knows that you need to store excess generated energy in batteries for later or to have a backup generator for when night comes. What you are doing is the classic strawman.

If electricity is cheap in the daytime and scarce/expensive at night, the market will figure it out.

Maybe that means people have incentive to charge their cars at work. Maybe it means entrepreneurs buy excess electricity on the spot market during the daytime, use it to pump water uphill, and use the potential energy of that water to generate more expensive electricity at night. (Is that process lossy? Sure! But the market will only reward it if it provides a net benefit, so it's all good. Same for battery / ultracapacitor / other technologies -- if they're a good fit for the problem, someone will make money using them; if not, they won't).

Peak electricity demand is lunch-time and supper-time. Lunch-time is pretty much covered with solar, and depending where you live, a good chunk of supper-time is too. "Powering lights" is by no means the biggest use of energy, even if lights is all you see when you look outside at night-time. The biggest energy consumption comes from things used to make heat (cooking, hot water) and everything with a motor (cooking again, air conditioning, laundry). Your light bulbs (especially nowadays with LED's and compa

We have an energy surplus at night, due to things like nuclear facilities that run at the same output no matter the demand. Really, we need to expand our power system to handle larger peak energy during the day, when everyone is running their air conditioners. Expanding into more nuclear is politically difficult. Gas and Coal are polluting. Solar would help us during the day, when power usage is highest.

So no, no one energy source can be our only generation point. But solar could definitely help when i

Roger Angel is an astronomer. He's done good work on telescope design. Hence the fascination with mirrors.

There have been many elaborate schemes for solar power using collecting optics. [solar-concentrators.com] The mirrors and supporting machinery usually end up costing more than you save by having less silicon area. Flat solar panels are simple to install, can be made resistant to high winds, and require minimal maintenance.

Yes, when I saw the picture of their device I was concerned about winds.
They make a big deal about the fact that it's made of out lightweight alloys. But the forces due to wind would be much greater than the gravitational forces, and the structure doens't look as if it is built in a way that you could collapse it somehow if a storm is expected.

Solar concentrators have a disadvantage that they only work on clear days. On cloudy days, the light won't concentrate, and they're useless. Still useful in some areas with lots of direct sunshine, but not where I live, for instance.

The article seems imply that the fact that it requires so much maintenance is good because it's all local. But no matter where the maintenance jobs are, they cost money, and thus make it uncompetitive...